Two-temperature refrigerating apparatus



July 24, 1956 Filed Jan. 13, 1955 IN VEN TOR.

Ziwm 5527/7025 BY W. GE. Ala/ 14 HIS ATTORNEY United States Motors Corporation, Detroit, Mich., a corporation of Delaware Application January 13, 1955, Serial No. 481,508

9 Claims. (Cl. 62-4) This invention relates to refrigerating apparatus and more particularly to a combination refrigerator and freezer.

It is an object of this invention to provide a combination refrigerator and freezer in which a first refrigeration system cools the low temperature freezer compartment and a second refrigeration system cools the higher temperature unfrozen food storage compartment.

Another object of this invention is to so arrange the two systems that it is possible to transfer heat from the one system to the other while defrosting the one system during its off cycle.

More particularly it is an object of this invention to place the receiver of the relatively high temperature system in thermal exchange relationship with the evaporator of the relatively low temperature system whereby the receiver may be used to condense vaporized refrigerant leaving the high temperature evaporator during the defrosting of a high temperature evaporator.

Still another object of this invention is to provide each of the refrigerating systems with its own superheat removing coil and to provide common fins for both of the superheat removing coils.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings, wherein a preferred form of the present. invention is clearly shown.

in the drawing:

The sole figure of the drawing schematically shows the construction and arrangement of the refrigeration systems and their relationship to the food storage compartments.

Referring now to the drawing wherein a preferred embodiment of the invention has been illustrated, reference numeral 10 generally designates an insulated refrigerator cabinet having a first relatively low temperature compartment 12 for storing frozen foods and a second relatively high temperature compartment 14 for storing unfrozen foods. For purposes of illustration the freezer compartment '12 has been shown disposed beneath the higher temperature compartment 14 whereas these compartments could be arranged in side-by-side relationship. In the embodiment shown, separate doors 16 and 18' have been provided for the separate compartments whereas a single door could be used for both compartments if desired. The doors 16 and '18 are of the vertically movable type, more fully shown and described in copending application Ser. No. 404,563, filed lanuary 18 1954, to which reference is hereby made for more complete description of the doors and door actuating mechanism.

Each food storage compartment is preferably provided with its own refrigerating system. Thus a first refrigerating system generally designated by the reference numeral 20 serves to refrigerate the frozen food compartment 12. This first system comprises an evaporator 22 located in the compartment 12. The vaporized refrigerant leaves the evaporator 22 through the suction line 24 which 'atent 2,755,634 Patented July 24, 1956 leads to conventional sealed motor compressor unit 26. The compressed refrigerant leaving the compressor first flows into a superheat removing coil 28 wherein the superheat of the compressed refrigerant and entrained lubricant is removed. The mixture of compressed refrigerant and lubricant is then returned to the motor compressor unit 26 in accordance with standard practice so as to separate the entrained lubricant from the refrigerant be fore discharging into the condenser 30. The condensed refrigerant is applied to the evaporator 22 through a fixed restrictor 32 which serves to reduce the pressure on the refrigerant and the evaporator 22. A thermostat 34 which is preferably located in thermal exchange rela tionship with a portion of the evaporator 22 serves to operate the motor control switch 36 for starting and stopping the operation of the motor compressor unit 26.. The motor control switch is preferably of the type which starts the motor whenever the temperature of the evaporator 22 reaches 12 F. or higher and shuts off the motor at 4 F. The refrigeration system thus far described is intended to represent a conventional refrigeration system of the type used in frozen food storage cabinets.

The refrigerating system for cooling the relatively high temperatures food storage compartment 14 comprises a plate type evaporator 40 which is arranged in thermal exchange relationship with the contents of the compartment 14. The vaporized refrigerant leaving the evaporator 4t? returns to a second motor compressor unit 42 similar to the motor compressor unit 26. The compressed refrigerant and entrained lubricant is discharged into a. superheat removing coil 44 adjacent to the superheat removing coil 38. Common fin elements 46 are provided for both superheat removing coils with the result that the two coils may be handled and supported as one coil. Another advantage of this construction is that when only one of the motor compressor units is in operation the available fin surface for dissipating the heat is much greater than if the two coils had separate fins. After the superheat has been removed from the mixture of refrigerant and vapor this mixture is returned to the motor compressor housing 42 where the oil separates out in accordance with standard practice and the relatively oil free refrigerant flows to the condenser 48 where the refrigerant liquifies before entering the fixed restrictor 50 which is in thermal exchange. relationship with cold suction line throughout a portion of its length. The fixed restrictor then feeds the refrigerant at a reduced pressure into a receiver like receptacle 52 which is located in the frozen food storage compartment 12 so as to be arranged in thermal exchange relationship with the evaporator 22. Liquid refrigerant leaves the receptacle 52 through a line which then feeds the liquid refrigerant into the evaporator 40 during the on cycle of the motor compressor unit 42. This second refrigerating system, generally designated by the reference numeral 56, is of the selfdefrosting type wherein all of the frost which accumulates during the on cycle melts during the off cycle. This second refrigerating system 56 is controlled by a thermostat 60 located in thermal exchange relationship with the evaporator 40 and which cooperates with the control switch 62 for the motor compressor unit 42 so as to initiate operation of the motor compressor unit 42 whenever the temperature of the evaporator 40 exceeds 36 and so as to stop operation of the motor compressor unit 42 whenever the temperature of the evaporator 40 falls below l2. The evaporator 40 is preferably in the form of a plate located adjacent one of the walls of the compartment 14 and is small in size so that when the compressor stops operating the evaporator 40 will quickly warm up due to the relatively Warm air in the compartment 14. As the evaporator 40 warms up the liquid refrigerant in the evaporator vaporizes and tends to force some of the liquid in the passes "of the evaporator 40 to be returned to the receiver 52. Some of the refrigerant which has been vaporized in the evaporator 40 will return to the receiver 52 in vapor form but due to the cold temperature of the receiver 52 it Will recondense in the receiver 52 so as to be immediately available for reevaporation just as soon as the motor compressor unit 42 restarts. Upon starting of the motor compressor unit 42 the liquid refrigerant in the receiver 52 will very quickly be pulled into the evaporator 40 and the upper portion of the receiver 52 will at times contain little or no liquid refrigerant. This is particualrly true toward the end of the on cycle of the system 56 when the evaporator 40 will be operating at a lower temperature than that being maintained in the frozen food storage compartment 12.

By virture of the above described arrangement of parts the two refrigerating systems operate very efficiently and it is not necessary to apply any external heat to the systems for defrosting the evaporator 40. Furthermore the time required for defrosting the evaporator 40 is made very short due to the fact that the receiver 52 in effect becomes a condenser which helps to accelerate the removal of all liquid refrigerant from the evaporator 40 immediately upon stoppage of the motor compressor unit 42. Still another advantage of the arrangement shown is that the liquid refrigerant which accumulates in the receptacle 50 during the off cycle is refrigerated and is made available for immediate reuse in the evaporator 40.

While the form of embodiment of the invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted, as may come Within the scope of the claims which follow.

What is claimed is as follows:

1. In a refrigerator assembly having a first relatively low temperature frozen food storage chamber and a second relatively high temperature unfrozen food storage chamber, a first refrigeration system including a first evaporator in said first chamber and refrigerant liquefying means for supplying liquid refrigerant to said first evaporator, a second refrigeration system including a second evaporator in said second chamber, a receiver located in thermal exchange relationship with said first evaporator for storing liquid refrigerant for said second evaporator, a second refrigerant liquefying means for supplying liquid refrigerant to said receiver, and means for connecting said second evaporator, receiver and said second liquefying means in refrigerant flow relationship.

2. In a refrigerator assembly having a first relatively low temperature frozen food storage chamber and a second relatively high temperature unfrozen food storage chamber, a first refrigeration system including a first evaporator in said first chamber and refrigerant liquefying means for supplying liquid refrigerant to said first evaporator, a second refrigeration system including a second evaporator in said second chamber, a receiver located in thermal exchange relationship with said first evaporator for storing liquid refrigerant for said second evaporator, a second refrigerant liquefying means for supplying liquid refrigerant to said receiver, and means for connecting said second evaporator, receiver and said second liquefying means in refrigerant flow relationship, first means for controlling the operation of said first refrigerant liquefying means in response to refrigeration requirements in said first compartment, and second means for controlling the operation of said second liquefying means in response to refrigeration requirements in said second compartment.

3. In a refrigerator assembly having a first relatively low temperature frozen food storage chamber and a second relatively high temperature unfrozen food storage chamber, a first refrigeration system including a first evaporator in said first chamber and refrigerant liquefying means for supplying liquid refrigerant to said first evaporator, a second refrigeration system including a second evaporator in said second chamber, a receiver located in thermal exchange relationship with said first evaporator for storing liquid refrigerant for said second evaporator, a second refrigerant liquefying means for supplying liquid refrigerant to said receiver, and means for connecting said second evaporator, receiver and said second liquefying means in refrigerant flow relationship, first means for controlling the operation of said first refrigerant liquefying means in response to refrigeration requirements in said first compartment, and second means for controlling the operation of said second liquefying means in response to refrigeration requirements in said second compartment, said second controlling means comprising a thermostat arranged in thermal exchange relationship with said second evaporator for starting and stopping operation of said second refrigerant liquefying means at predetermined high and low second evaporator temperatures whereby said second evaporator defrosts on each off cycle.

4. In a refrigerator assembly having a first relatively low temperature frozen food storage chamber and a second relatively high temperature unfrozen food storage chamber, a first refrigeration system including a first evaporator in said first chamber and refrigerant liquefying means for supplying liquid refrigerant to said first evaporator, a second refrigeration system including a second evaporator in said second chamber, a receiver located in thermal exchange relationship with said first evaporator for storing liquid refrigerant for said second evaporator, a second refrigerant liquefying means for supplying liquid refrigerant to said receiver, and means for connecting said second evaporator, receiver andsaid second liquefying means in refrigerant flow relationship, said receiver having an inlet adjacent its one lower edge and having an outlet adjacent its other lower edge.

5. In a refrigerator assembly having a first relatively low temperatre frozen food storage chamber and a second relatively high temperature unfrozen food storage chamher, a first refrigeration system including a first evaporator in said first chamber and refrigerant liquefying means for supplying liquid refrigerant to said first evaporator, a second refrigeration system including a second evaporator in said second chamber, a receiver located in thermal exchange relationship with said first evaporator for storing liquid refrigerant for said second evaporator, a second refrigerant liquefying means for supplying liquid refrigerant to said receiver, and means for connecting said second evaporator, receiver and said second liquefying means in refrigerant flow relationship, each of said refrigeration systems including a compressor and a superheat removing coil at the outlet of each compressor said superheat removing coils being mounted adjacent one another and having common fins.

6. In combination, means forming a frozen food storage compartment, means forming an unfrozen food storage compartment, a first refrigerating system including a first evaporator for maintaining said first named compartment at below freezing temperatures, a second refrigerating system for refrigerating said unfrozen food storage compartment, said second system comprising a compressor, a condenser, a receiver located in thermal exchange relationship with said first evaporator, a second evaporator in said unfrozen food compartment, and refrigerant flow connections between said compressor, condenser, receiver, and said second evaporator, and control means for operating said second system on a defrosting cycle.

7. In combination, means forming a frozen food storage compartment, means forming an unfrozen food storage compartment, a first refrigerating system including a first evaporator for maintaining said first named compartment at below freezing temperatures, a second tofrigerating system for refrigerating said unfrozen food storage compartment, said second system comprising a compressor, a condenser, a receiver located in thermal exchange relationship with said first evaporator, a second evaporator in said unfrozen food compartment, and refrigerant flow connections between said compressor, condenser, receiver and said second evaporator, and control means for operating said second system on a defrosting cycle, said receiver and said refrigerant flow connections being arranged so as to prevent gravity flow of refrigerant from said second evaporator to said receiver.

8. In combination, means forming a frozen food storage compartment, means forming an unfrozen food storage compartment, a first refrigerating system including a first evaporator for maintaining said first named compartment at below freezing temperatures, a second refrigerating system for refrigerating said unfrozen food storage compartment, said second system comprising a compressor, a condenser, a receiver located in thermal exchange relationship with said first evaporator, a second evaporator in said unfrozen food compartment, and refrigerant flow connections between said compressor, condenser, receiver, and said second evaporator, and control means for operating said second system on a defrosting cycle, said frozen food storage compartment and said unfrozen food storage compartments being disposed in juxtaposition within an insulated cabinet.

9. In combination, means forming a frozen food storage compartment, means forming an unfrozen food stor age compartment, a first refrigerating system including a first evaporator for maintaining said first named compartment at below freezing temperatures, a second refrigerating system for refrigerating said unfrozen food storage compartment, said second system comprising a compressor, a condenser, a receiver located in thermal exchange relationship with said first evaporator, a second evaporator in said unfrozen food compartment, and refrigerant flow connections between said compressor, condenser, receiver, and said second evaporator, and control means for operating said second system on a defrosting cycle, said frozen food storage compartment and said unfrozen food storage compartments being disposed in juxtaposition within an insulated cabinet having access openings in a. vertical wall of said cabinet, and vertically slidable doors for closing said access openings.

References Cited in the file of this patent UNITED STATES PATENTS 1,954,136 King Apr. 10, 1934 2,078,343 Replogle Apr. 27, 1937 2,479,732 Dodson Aug. 23, 1949 2,692,481 Schweller Oct. 26, 1954 

